The invention relates to a copying apparatus with a guide for an insertable paper holding cassette, especially for a paper holding cassette for holding a stack of sheets of paper coated on one side thereof. In preferred arrangements, the cassette is formed as a flat rectangular holder bordering the stack of sheets of paper at the sides, bottom, top, and one end. At the other end of the cassette which is to be inserted into the copying machine, openings are provided in the sidewalls, in the top wall, and in the bottom wall so that the sheets of paper are freely accessible to be delivered into the machine.
Copying machines of the above mentioned kind are principally so called office copiers which are used by persons who are not especially skilled in the use and service of such machines. In practice it has been experienced that many difficulties arise because the cassettes are not correctly inserted into the copying machine. Although the cassettes are usually most clearly marked, it often happens that the cassettes are inserted with the sides reversed, which makes it impossible to make a copy with coated papers because the coated side is facing in the wrong direction. Frequently it also happens that the cassette is not brought correctly to its end in use position, which then can lead to the danger that the papers become jammed in the machine when copying is attempted.
The invention is based upon the proposition that a copying machine and the corresponding cassettes of the above mentioned type are so constructed that mistakes in the insertion of the cassette are avoided with certainty. The invention contemplates the provision of apparatus for detecting the correct insertion of the cassette, which apparatus includes a detection switch constructed in the form of a pivotal control lever with two arms extending parallel to the floor or bottom of the cassette. The first arm is engageable in a side edge of the cassette with a catch or receiver. The second arm is engageable into an opening in the cassette sidewall, spaced longitudinally from the catch, which opening accommodates pivoting movement of the lever by permitting the insertion of the second arm.
Through the arrangement of the invention it is obtained that the detection apparatus always indicates the conditions where no cassette is in the copying machine and when a cassette is incorrectly inserted or is not in its exact use position. As the cassette is inserted, the first arm of the control lever extends into the paper stack between two sheets without being activated by the sheets. The follower catch of the cassette sidewall effects a pivoting of the control lever. This pivoting movement is however only possible when the control lever is able with its second arm to extend inwardly into the opening of the cassette, so that there is a switching of the detection switch only if the cassette is correctly inserted with respect to its sides and is also moved into its exact in use position.
In order to simplify the penetration of the first arm of the control lever into the stack of paper and to avoid the danger of damage to individual sheets, especially preferred arrangements include construction of the arms of the control lever with tapered or beveled cut edges engageable with the stack of sheets. Because the second arm also extends sidewise into the stack of paper, it is advantageous if the end of the second arm engageable into the cassette is also sharpened.
In order to assure that the free forward edge of the stack of paper does not unintentionally activate the control lever and therewith the detection switch, preferred embodiments of the invention provide that the control lever is provided with a spring which is loaded to push the lever towards its base position. This spring is so configured that it has sufficient strength to prevent the pivoting of the lever only in reaction to the insertion of the lever arm into the paper stack.
In order to assure that only a small movement of the control lever does not lead to an activation of the detection switch, it is preferable that the detection switch is constructed as a spring loaded micro-switch. With this arrangement, only after a certain movement of the control lever is the switch operation activated. Furthermore the switching is independent of the speed or slowness of the insertion of the cassette into the copying apparatus.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.